YAMAHA 05-13 YZ250,WR250F 5-VALVE , GAS GAS 10-15 EC 250F Series Piston Kit

Part Number 246270 (155626812)

UPC: 193564220592

Package contents: 1 Each per Box

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Description

As the leader in forged racing pistons, JE Pistons has applied over 75 years of experience to its wide range of pistons for Yamaha YZ250 / WR250F 5-Valve / WR F 5-Valve Engines JE Pistons are engineered, forged and machined 100% in the USA. Equipped with the following custom level features

JE pistons are all designed, forged, and machined in-house, allowing control over every step of the piston-making process. JE Pistons 7+ decades of experience in high-level racing has led to offering premium racing features, including full billet construction, EN plating, and purpose-designed coatings, to name a few.

Features & benefits

Forged in the USA using 2618 aluminum, yielding high tensile strength needed for high-demand performance applications
Race-inspired two-ring design promotes quick revving and throttle response for noticeable power
Designed specifically for Yamaha YZ250 / WR250F 5-Valve / WR F 5-Valve Engines to provide optimized performance durability
Proprietary Forged Side Relief (FSR) forging design minimizes friction and power loss with reduced skirt width and saves additional weight with a shorter wrist pin
Includes high-quality wrist pins, locks, and JE Pro Seal premium piston rings
Made 100% in the USA
Accumulator Groove: A specialty groove between the top and second ring provides added volume for blow-by gases. This helps reduce pressure between the rings, improving top ring seal and minimizing ring flutter at high cylinder pressures.
Pin Fit: The pin bore is precision honed to attain an exact pin clearance. Clearances typically range from .0003 to .0010 between the wrist pin and pin bore.

Specifications

3D Undercrown Milling	No
Accumulator Groove	Yes
Anodize Top Ring Groove	No
Bore Diameter	77.00 mm
Combo 2	No
Compression Height	0.878
Compression Ratio	0.54513888888889
Compression Ratio Actual	13.50:1
Contact Reduction	No
Country Of Origin	USA
Cylinder Head	Brodix SR20
Double Pin Oilers	No
DVGP	No
Econo Undercrown Milling	No
EN Plating	No
Engine	YAMAHA
Engine Displacement	250
Engine Stroke	2.110 in
Engine Type	ICE
Exhaust Angle	13
Exhaust Depth	.145
Exhaust Diameter	1.050
Forging Type	FSR
Gas Distribution	No
Intake Angle	18
Intake Depth	.145
Intake Diameter	1.000
Lateral Gas Ports	No
Mill Undercrown	No
Oil Groove Width	0.05850 in
Oil Ring Thickness	0.0585 in
Pin Fit	Yes
Piston Average Weight	170 gr
Piston Head Type	Dome
Piston Material	2618
Piston Series	JE Pistons
Piston To Wall Clearance	-0.002 in
Piston Volume	0.00 cc
Product Market	Off-Road
Product Type	Engine Piston Kit
Ring Set - Recommended	JC3301-3031
Ring Set Included	Yes
Ring Set Part Number	JC3301-3031
Skirt Coat	No
Smooth Crown Finish	No
Thermal Crown	No
Top Compression Ring Thickness	0.0360 in
Top Groove Width	0.03600 in
Tuff Skirt	No
Ultra Dome	No
Ultra Groove	No
Ultra Groove Plus Gas Port	No
Vertical Gas Ports	No
Wrist Pin Length	1.650 in
Wrist Pin Material	9310 Nickel Carbon Steel Alloy
Wrist Pin Outer Diameter	0.630 in
Wrist Pin Wall Thickness	0.120 in

Warranty

30 Months

California residents

WARNING: This product can expose you to chemicals including nickel, which is known to the State of California to cause cancer. For more information go to www.P65Warnings.ca.gov.